Provides APIs to map error message to predefined error code

[boqiu]

Currently, it is very hard for client to handle the errors returned by SDK. So, SDK could provide API to map error message to error code or return error code along with error message. So that:

1. Client could handle all errors properly.
2. Support i18n on UI.

Moreover, SDK should add necessary documents or comments to clarify the possible root cause and solutions for each error code or message.

In the end, this is a common requirements for all SDKs.

[Pana]

I have collected an error list for estimate and sendRawTransaction we will design an error code feature to solve this problem